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can it be done? 20mpg 5.3 swap

MAX89K5

MAX89K5

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Well y'all, the time has come. To justify a 5.3 swap for me, I need to get 20mpg. I am losing my econbox Hyundai to a family member in need, and i need to decide if i should buy another disposable car, or spend the money on the swap. Some specs on my 89 k5 are 4.10 gears, 35" tires; I will run a 4l60e and the 241 Tcase. What are your thoughts on this, can it be done? I have read about a mild comp cam that boosts mpg and torque, any recommendations? Thanks guys :D
 
Not seen it done but sure can come very close! Are you heavy footed? 35's might hurt you some what there but sure if you get it speced right and due some excessive tuning it is possible.
 
With mpg in mind and this being my DD, I would try my best to stay out of the skinny pedal. Once the novelty wore off of the swap, I'm sure my driving habits would improve. Anything has got to be better than the 8mpg I'm getting now with my tired tbi 350.
 
You'll never see that kind of mileage. If you had Dmax and allison maybe.
You will see better than 8mpg. Hell my truck gets 11.
 
I am just weighing the costs, I commute roughly 35 miles round trip per day. I better get used to higher fuel costs than my hyundai lmao
 
From what I have read more like 14 to 16 occasionally going to 18.

If you want 20 swap in a 6.5 turbo diesel motor.
 
My 5.3 stock Yukon XL gets 20MPG if its highway only and under 65. I run the 5.7 in the K5 lean at cruise and can barely get 15. So my guess is that you would be somewhere in between there.
 
A 5.3 swap is no Saturday project. What are you going to drive for weeks while you do,the swap? The numbers don't add up from a mileage perspective alone. If you want it for the skinny pedal fun then ok. Otherwise I'd run the numbers on an econoox.
 
My LB7 Duramax / 6 speed manual gets around 22mpg. At 50mph. Running at 75mph it gets 16 or 17 mpg. Still not bad for a truck with the aerodynamics of the broad side of the barn geared way too deep and on 37s though.

My 5.3L 4dr Tahoe (bone stock) gets on average 15 mpg. Upwards of 20 on the highway but it drops to about 12 in town.
 
Agree on car vs. truck. 20MPG in the truck vs. 40MPG+ in an econobox, assuming you could even get 20MPG out of the truck, which is questionable.

mid-2000's Accent can be had for $1500-3000 around here, just do the math and see how long it would take you to break even, once you take the cost of the 5.3 swap out of the picture. I assume the components for the swap would cost you nearly that much alone.

I'm no fan of econoboxes, but double+ the mileage is nothing to scoff at when you start driving a fair bit. Tire replacement is going to be substantially less as well. :)
 
The only way you could get 20mpg is if you trailer your rig half way to its destination. An econobox for mileage, a Square body for pleasure....
 
I have been very happy with my VW TDI... 42-50 mpg commuting pays for the payment and insurance over a 15 mpg truck. My commute is 25 miles one way when I don't have school, closer to 55 miles one way with school.
 
My 5.3L 4dr Tahoe (bone stock) gets on average 15 mpg. Upwards of 20 on the highway but it drops to about 12 in town.
Click to expand...

2nd that. My wife's new 07 5.3 sub gets the same and it's a heavy beast
 
my mom had an 04 Yukon with the 5.3, pulling our camp trailer up the mountain she still got 20MPG
 
We just did a trip last month here that took us all day to do, a little sight seeing trip, I kept every fuel receipt, kept track of exact mileage and how much fuel we used. I figured everything up to right about 19mpg, mostly highway driving, we did run up and down a nice mountain route up through some national park area too.

The Avy seems to get about 19-21 mpg on the highway, 21 area when the highway is mostly flatland stuff and not pushing it too hard around that 75 mph mark. Around town, so far it's doing about 16.

We drive very lightly in an attempt to save as much gas as possible, funds get a touch thin for the most part a lot of times due to other expenses :doah: so gassing up the truck takes a back seat a lot of times.

This is in the '05 with the 5.3 and probably is due for some injector service as well, just had the engine rebuilt about 2 years back now.
 
Thanks for all of the input guys. I've got a line on a wrecked 02 z71 minus the front clip for $1200. Only thing I'm scared of is its got 135k on the clock, should I consider it or keep looking? Its got a fairly straight body and I could part the rest of it out/scrap it to recoup funds.
 
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